In order to suppress deterioration of an electrolyte membrane included in a fuel cell, for example, a technique disclosed in Patent Literature 1 calculates a creep deformation amount of the electrolyte membrane and its cumulative value from the temperature or the humidity of the electrolyte membrane and gives a warning when the cumulative value exceeds a predetermined value. The technique described in Patent Literature 1 suppresses the electrolyte membrane from being dried and cracked by giving a warning.